A wireless communication system has been prevalently developed in order to provide various kinds of communication services such as voice, data, or the like. Generally, the wireless communication system is a multiple access system that may share available system resources (bandwidth, transmission power, or the like) to support communication with multiple users. Examples of a multiple access system may include a code division multiple access (CDMA) system, a frequency division multiple access (FDMA) system, a time division multiple access (TDMA) system, an orthogonal frequency division multiple access (OFDMA) system, a single carrier frequency division multiple access (SC-FDMA) system, or the like.
The wireless communication system generally uses a single bandwidth so as to transmit data. For example, a second-generation wireless communication system uses a bandwidth 200 KHz to 1.25 MHz and a third-generation wireless communication system uses bandwidth of 5 MHz to 10 MHz. In order to support the increasing transmission capacity, the latest 3GPP LTE or 802.16m continues to extend its own bandwidth of up to 20 MHz or more. In order to increase the transmission capacity, it is essential to increase a bandwidth. However, even when the required level of services is low, increasing the bandwidth may greatly increase power consumption.
Therefore, a multi-carrier system to define carriers having a single bandwidth and a central frequency and transmit and/or receive data in a wide band through a plurality of carriers has been emerged. The multi-carrier system simultaneously supports a narrow band and a wide band by using one or more carriers. For example, when a single carrier corresponds to a bandwidth of 20 MHz, the multi-carrier system supports a bandwidth of 40 MHz by using two carriers.
Generally, a guard band is disposed between carriers in the multi-carrier system. Generally, the guard band is a null region that does not transmit any data. If the guard bands between contiguous carriers can be used, additional radio resources may be secured. A need exists for a method capable of using the guard band in the multi-carrier system.